Graphene sheets are two-dimensional, conjugated carbon structures which are only one to a few atoms thick. Graphene sheets are currently among the most studied nanomaterials for potential applications in electronics, energy harvesting, conversion, and storage, polymer composites, and others. Graphene sheets with the most ideal structures are experimentally obtained via mechanical exfoliation (for example, via the “Scotch Tape” method), which only produces very small quantities. For the bulk preparation of graphene, one of the most popular methods typically starts with strong oxidation of natural graphite into graphene oxide (GO) that is dispersible in aqueous solutions as exfoliated monolayer or few-layered sheets. The exfoliated GO sheets may then be chemically or thermally converted into graphene—or more accurately “reduced graphene oxide” (rGO). Compared to the graphene sheets prepared from mechanical exfoliation or chemical vapor deposition methods, chemically exfoliated rGO sheets typically have more defects.